We propose to implement a radically altered design for a retinal prosthesis, with the goal of restoring a useful level of vision to patients blind with retinitis pigmentosa or macular degeneration. Nearly the entire bulk of the implant will be attached to the outer wail of the eye (sclera), with only a thin microelectrode array penetrating the sclera to electrically stimulate the retina subretinally. This biocompatible design avoids intrusive vitreal surgery, the need for tacks or glue for attachment to the retina, the release of heat by intraocular electronics, and motion-induced stress on the retina from the implant. Specific objectives are to: * Redesign the implant microchip to add the capacity to transmit data from the implanted electrodes back to engineers and clinicians (Prof. John Wyatt, Electrical Engineering Dept., MIT - BRP Lead Institution) * Permanently coat the microelectrode array with biocompatible materials to prevent a foreign body response by the retina (Prof. Carmen Scholz, Department of Chemistry, Univ. of Alabama, Huntsville), * Permanently shield the microelectronics from saline by placing them in a novel hermetically sealed package that allows for a large number of signal inputs and outputs and is sufficiently tiny to permit chronic surgical implantation on the outside wall of the eye (Dr. Douglas Shire, consultant at Cornell Nanofabrication Facility), * Surgically test prototypes at various stages of development in the dog eye and provide feedback about necessary modifications (John Loewenstein, M.D. retinal surgeon at the Mass. Eye and Ear Infirmary).